Pressure gauge



Sept. 4, 1928.

H. F. KRAFT PRESSURE GAUGE Original Filed March 25, 1921 vwemtoz .ber, after the reading operation, is restored" Patented Sept. 4, 1928 7 can" no: status earner orrtc a.

HENRY IP'.

KRAFT, or mnenwooio, new JERSEY; EDGAR J. PHILLIPS AND EARL A}.

BARR 'nxnonrons or HENRY r. KRAFT, nnonAsnD.

PRESSURE GAUGE.

Application filed March 25, 1921, Serial No. 455,680. Renewed January 7, 1927.

illlS invention relates to pressure gauges,

a. d provides a gauge which is particularly -iaoted for use in connection with pneutires.

In gauges of this type it is customary to provide an indicating member with means for holding such member in indicating poion after the gauge is removed from the ly of two types, in one of which the p *eacseonsive member, such as a pisposition together with the indicating memby a catch or similar device, all of the parts being held with the loading spring under the tension which has been given to the spring by the air pressure. Such gauges ave the merit of a positive holding of the arts until released. In the second type of huge the indicating member is disconnectd from the piston or other pressure-responiive member, and is held in pressure-indicatposition by friction or the like. The pressure-responsive member in this type returns to its initial position as soon as the pressure is relieved, and the indicating memby pushing it baclrby hand to Zero position. Thi s avoids the holding of the spring under coinnession and the snao in back of the indicator bar, but has the disadvantage that sometimes the bar is inadvertently pushed in before the reading is taken, with the result that a false reading is obtained.

According to the present invention I provide a construction in which, to a large eX- tent, the advantages of both methods are availed of, and the disadvantages obviated. In the preferred form of the present invention I provide an indicator which is detached or separated from the pressure-responsive member, and which is securely held in its indicating position until intentionally displaced.

Inthe drawing, whereinil have shown the preferred form. of'the. in ventio n,

Figure l is a side elevation of the gauge;

Fig. 2 is an enlarged diametrical section;

Fig. 3 is a top view of the upper sleeve;

Fig. 4 is a section on the line 4& in Fig. 2;

Fig. 5 is a sectional view, partly in perspective, of the upper cap;

Fig. 6 is a detailed perspective view of the top spring holder.

1 e valve. Such gauges have hitherto been ten or the like. has been held in its displaced Referringjto the drawings, let A indicate the gauge as a whole, which is: shown as formed with a cylindrical casing 13 having a foot portion: C, the latter being displaced to a slightly angular position in order, to bring'the gauge caslng out of line with the ilator E and packing ringF, the former-being adapted to open the tire valve, and the latter adapted to make a tight joint between the gauge casing and the tire valve casing.

Within the casingv B is some form of pressure-responsive member such as. the piston G, shown as comprising the usual packing, and being adapted to move along the casing in a lengthwise direction. The loading spring is indicatedby the reference let ter H, and is designedt'o resist the-move" ment of the piston from its lowermost or zero position. I v

According to the present invention, the indicator D is disconnected orseparate from the piston G, so that while it is 'moyed to- I wardthe pressure-indicating position by the piston, the latter does not move it back 7 to zero position after the pressure is re moved and the piston returns. In the pre ferred construction illustrated, the indicator member is showrias afiat gauge-bar which proJects through the outer end of the easmg, disclosing an appropriate scale wh ch indicates the pressures; My invention pro-- vides means for securely holding the detaehed 'au 'e barin it's ressure-indicatin b positions, and by securely holding is meant such holding as will avoid accidental displacement such as is liable in the case of an indicator which is held solely by friction. Preferably alsm the invention includes means for positively holding the gauge-bar against an-inward movement until intentionally displaced; There is muchless danger of an accidental outward movement of the gauge bar or other indicat0r,-than of an inward movement. the fact that it requires a pulling movement to move it outwardly, while the mere accidental contact with the finger or any other object may be sufiicient to move it inwardly.

The simplest form of the invention is that illustrated, wherein the gauge bar is provided with teeth or serrations I which are de- This is due to I guide for the gauge bar.

signed to .engage a wall, such as J, on the gauge casing, or any other appropriate part of the gauge. In the construction shown the device is provided with a cap or sleeve K having'an aperture L through it, through which the gauge bar passes. Means are provided for normally urging the gauge bar in a direction which will tend to engage the teeth I with the wall J, and in the construction shown this is accomplished by a spring M which has a circular portion lying within the cap, and. an upwardlyextending arm ll curvedto .iit the back of the gauge bar at 0, so that the latter may move along the spring with a constant tendency to engage the wall J or its equivalent. The teeth are so pitched as to permit them to slide past the wall J during the outward movement of the gauge bar, and preferably are provided with lateral tacos P which positively prevent the gauge bar from being retracted un'" less first disengaged from the wall J. This disengagement may be accomplished, in the construction shown, by merely pressing in the gauge bar laterally to disengage the teeth, and pushing it inwardly to restore the gauge bar to zero position.

In constructing the gauge it vide a thimble (.2 at the top or a smnlar thnnble R on the piston, such thunbles actm as 'uides or seats ior the ends oi D We the sol-in lhe thimble ma be advanl x a r tageousiy or such a size as to fit the end ot s best to prcthe an e and in assemblin the circular I i") b 7 D7 portion of the springM may be placed on top of the thimble Q, the several parts being held in position by the cap K. The axial flange ot' the. thimbl-e Q also serves as a The thimblc provides a recess which isadmirably adapted to receive the end of the gauge bar so as to maintain the same in substantially central or axial position within the casing.

In operation, as the p1ston moves upwardly, the gauge bar is also moved upwardly,

' the teeth riding along the wall J and maintaining contact therewith by the operation of the spring M. lVhen the gauge is removed from the tire valve the gauge bar remains with one of its teeth engaging the wall J, while the piston returns to its lowermost position. hen the teeth are constructed as shown, the gauge bar resists accidental diplacement in either direction. In order for the gauge bar to moveoutwardly, the spring must be pressed backward. As a 1e gauge, and

positively resist movement unless this move- .ment is both inward and sidewise, which is very seldom the case in use. It is not essential that the teeth be provided with strictly lateral portions, since some slant may be given to the lower faces, but it is preferable that there should be a positive resistance to displac ment in the direction of restoration to zero.

lVhile I have shown and described one form of the invention, it will be understood tha 1- do not wish to be limited thereto, since various changes may be made therein without departing from the spirit of the invention; and it is also apparent that the improvements are applicable to other types of gauges.

. N hat I claim is Y I l. A pressure gauge for the valves or the like, comprising a casing having an open ng '11 its top, a piston in said casing, a loading spring for said piston, a detached gauge bar extending within the spring and through the opening in the end of said casing, said g ge barhaving teeth formed therein, a

1' carried by the casing, and a spring for rging the bar against said cap so that the 'eeth engage the cap, said spring com-prising frA a section engaged by said cap tov anchor 51 spring, and a section engaging the said Jill.

sive member therein, a slidable gauge bar detachcd from but adaptedto be moved by said PIQSSUK'G*1QSPOI1S1V6 member in one direction,

said pressure-responsive member having means adapted to receive said gauge bar and permit it. to be tilted with respect to the casing.

In witness whereof, I have hereunto signed my name.

HENRY P. KRAFT. l 

